An Electronic Article Surveillance (EAS) system is designed to prevent unauthorized removal of an item from a controlled area. A typical EAS system may comprise a monitoring system and one or more security tags. The monitoring system may create an interrogation zone at an access point for the controlled area. A security tag may be fastened to an item, such as an article of clothing. If the tagged item enters the interrogation zone, an alarm may be triggered indicating unauthorized removal of the tagged item from the controlled area.
Desirable properties for an EAS system may include having larger interrogation zones and smaller, more flexible, security tags. These properties, however, are typically inversely proportional. For example, EAS systems using microwave signals typically have wider coverage areas but need larger security tags. Similarly, EAS systems using low frequency signals typically have narrower coverage areas but allow for smaller security tags. Consequently, there may be need for improvements in conventional EAS systems to solve these and other problems.